Benchmark LA4 vs SPL Elector vs PS Audio StellarGold

Seems like you made the right choice. The SPL is really nice too but I think the LA4 was the right call if you are focused on instrument detail and soundstage, the Benchmark was probably the best bet.

UPDATE:

I purchased a used Benchmark LA4 and a pair of PS Audio M700 mono blocks from a seller listing both. Got a great deal on the LA4 by also buying the M700 pair. I honestly expected to flip the M700 pair.

The LA4 was an amazing upgrade over the NAD C165BEE. It should be at double the MSRP. The improvement was more than I expected with wider soundstage, a bit more depth, and improved separation. After a couple of days I then inserted the M700s in place of the Nakamichi PA7Aii. I was not expecting any improvement and was hoping to sell them and look for something else in the future. There was a definite improvement in clarity and instrument separation (essentially what I was initially hoping for with the LA4). The end result was more than I had possibly hoped for.  The confirmation came from wife when she said, "the stereo seems so much clearer.  I like it."  

I listed the NAD and Nak for sale and the Nak sold almost immediately. I expect the NAD to sell soon.

This got me thinking what else should I upgrade. It didn’t take long. I just purchased a PS Audio DirectStream Mk1 DAC from TMR. They are having a great sale on refurbished PSA DS Mk1 units. Should have it in a few days to replace my Bifrost 2/64 (may sell, or move to my 2nd system).

Hopefully I am done with my case of upgraditis.

I have not heard the SPL, I was considering it at one time. I already had a LA4 and needed another preamp for another system I was building.

In terms of being quiet I think the LA4 is going to be hard to beat. You should compare the measurements to verify. The LA4 runs warm which is usual for a Benchmark component. In terms of sound, it really does not have any. If your other gear sounds good, then the LA4 will let you hear that other gear without decorating the sound. The volume clicks and I like that. It is also the best volume control I have owned. All amps I have tried with is work perfectly, I cannot say the same for another LA4 like preamp, the Topping pre90.

If I was not going to get another LA4 (for variety), I wanted another preamp that had similar attributes of the LA4, and I got it with the Holo Serene preamp. It is a touch warmer than the LA4 and the volume is not as robust as the LA4’s. However, it does sound very similar to the LA4 (almost no sound). It is likely in-between the SPL and the LA4 in terms of sonics. I think the Serene works very nicely with Class A amps.

When I purchased the SPL Elector the Benchmark was on my short list. 

It came down to the internal build for me along with both units having excellent reviews for neutrality and lack of presence. Having a Krell preamp as well I know what quiet is and the SPL has it in spades. The Benchmark has so much circuitry under the hood while the SPL has a nice design with high voltage rails. 

The kicker was the nice meters. I really enjoy watching them jump around sometimes. I use the XLR balanced input to a Pass Labs X350.5. True fully balanced I don't know.

By the way the volume pot is Alps and is nice and smooth and extremely well known in the pro realm. The steps are not that large.